Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: Thermal properties of carbon black aqueous nanofluids for solar absorption | Han et al. Nanoscale Research Letters 2011 6 457 http content 6 1 457 o Nanoscale Research Letters a SpringerOpen Journal NANO EXPRESS Open Access Thermal properties of carbon black aqueous nanofluids for solar absorption Dongxiao Han Zhaoguo Meng Daxiong Wu Canying Zhang and Haitao Zhu Abstract In this article carbon black nanofluids were prepared by dispersing the pretreated carbon black powder into distilled water. The size and morphology of the nanoparticles were explored. The photothermal properties optical properties rheological behaviors and thermal conductivities of the nanofluids were also investigated. The results showed that the nanofluids of high-volume fraction had better photothermal properties. Both carbon black powder and nanofluids had good absorption in the whole wavelength ranging from 200 to 2 500 nm. The nanofluids exhibited a shear thinning behavior. The shear viscosity increased with the increasing volume fraction and decreased with the increasing temperature at the same shear rate. The thermal conductivity of carbon black nanofluids increased with the increase of volume fraction and temperature. Carbon black nanofluids had good absorption ability of solar energy and can effectively enhance the solar absorption efficiency. Keywords nanofluids solar absorption carbon black photothermal properties rheological behaviors thermal conductivity Introduction The major resource of renewable energy comes from the sun. Solar energy utilization is very important in the background of global warming and reduction of carbon dioxide emission. Solar energy has been explored through solar thermal utilization photovoltaic p ower generation and so on 1-3 . Solar thermal utilization is the most popular application among them. In conventional solar thermal collectors plates or tubes coated with a layer of selectively absorbing material are used to absorb solar energy and then energy is carried away by working fluids in the form of heat 4 5
